Conventionally, there is known a technique for causing a small-sized information processing apparatus (personal computer) to function as a music playback apparatus (CD (Compact Disc) player).
In a small-sized information processing apparatus disclosed in Jpn. Pat. Appln. KOKAI Publication No. H09-101848, a mode switch is provided for causing the small-sized information processing apparatus to function as a music playback apparatus, and a process for CD playback is executed when power is turned on by the operation of this mode switch. In the process for CD playback, when power is turned on, diagnosis and initial settings are executed for an IDE controller to which a CD-ROM drive is connected, a bus bridge to which the IDE controller is connected, and an interrupt controller which mediates to deliver an interrupt signal of the IDE controller to the processor. In addition, a device driver for playing back a music CD, which is stored in the CD-ROM drive, is initialized. Further, power-saving is achieved by supplying power to only necessary components mainly including the IDE controller, bus bridge, interrupt controller, amplifier, CD-ROM drive and main memory, and stopping power supply to unnecessary components such as a fan and a hard disk drive.
As has been described above, in the prior art, in order to cause the small-sized information processing apparatus to function as the music playback apparatus, it is necessary to turn on power by operating the dedicated mode switch, and to execute the diagnosis and initial settings for the modules necessary for the CD playback, in the same manner as at the time of normal start-up. In addition, it is necessary to execute the program (device driver) for controlling CD playback.
Specifically, in the prior art, although the modules that are operated are limited to only some modules necessary for CD playback, these modules need to be set in the operative state through the process at the time of normal power-on. In addition, since the audio output is controlled by the program for controlling CD playback, power supply to the CPU and main memory, which are principal components of the small-sized information processing apparatus, cannot be cut off.